Blankholder actuating mechanism



Nov. 29, 1955 w. ERNST BLANKHOLDER ACTUATING MECHANISM 2 Sheets-Sheet 1 Filed July 23, 1951 FIG-3 INVENTOR WALTER ERNST BYP/l f Z C 4/ AT TOR NE YS Nov. 29, 1955 w. ERNST 2,725,025

BLANKHOLDER ACTUATING MECHANISM Filed July 23, 1951 2 Sheets-Sheet 2 l., La

INVENTOR WALTER ERNST ATTORNEYS forces.

United States Patent O BLANKHoLnEa aerrJArrNG Manganism Walter Ernst, Dayton, Ghio, assigner to The Commonwealth Engineering Company of Ohio, Dayton, (labio, a corporation of @bio Application .liuly 23, 1951, Seria! No. Zd

9 Claims. (Ci. 113-45) This invention relates to presses, particularly blankholder presses, and especially to actuating means for actuating the blankholder of a blankholder press.

In my copending application, Serial Number 115,901, filed September 15, i949, now Patent No. 2,672,836, I disclose a blankholder press in which there are pull-down rods connected with the blankholder associated with iiuid operable. means in the bed of the press for exerting the proper force on the blankholder.

The arrangement disclosed in the saidk application has proved to be satisfactory so far as the actuation of the blankholder is concerned and the obtaining of the proper forces on the blankholder and distribution of the said However, in said application, mechanical stops were relied on to halt the blankholder in a predetermined advanced position and to vary the blankholder force exerted by the blankholder at different points thereabout. Such mechanical stops have a tendency to get out of adjustment, and for that reason, it was necessary continuously to check the settings of the stops to maintain the blankholdery in proper operating condition.

,l In the referred to application, a single fluid operated means was arranged to exert force on two corners of the blankholder at one time, and because of this relatively lheavy and expensive mechanical linkage was required vbetween the fluid operable means andthe blankholder.

Also, in the said application, the piston of the iluid operabie means included a valve internally thereof by means of which the fluid in the iiuid operable means was only added to in the amount necessary to create the desired operatingy pressure in the fluid operable means. This arrangement is of distinct advantage in a press of they nature referred to, because, ordinarily, the fluid tank and. pressure pump for the press are mounted. on the top thereof, and the usual arrangement for supplying fluid to a. iin-id operated means in the bed would require long and i relatively large conduits. By the arrangement referred to, only a relatively small conduit must be supplied in order vto provide actuating iiuid to the fluid operated lThe present invention represents an advance over the blankholder actuating means disclosed in the application referred to, Inthe rst place, the present invention provides a separate uid operated means for each corner of the blankholder platen, thereby eliminating mechanical stops, and providing an arrangement whereby the force but without passing the said uid through the piston of the fluid operated means, thereby eliminating the provision of a valve Within the piston, resulting in a simpler, more inexpensive construction.

In particular, therprimary object of this vinvention is the "ice provision of an improved and simpliiied blankholder actuating means for a blankholder press;

Another object is the provision of an improved actuating means for the blankholder which is of the pull-down type.

Another object is the provision of a pull-down actuating device for a blankholder in which the individual forces exerted on the several corners of the blankholder can readily be controlled.

A still further object is the provision of a blankholder actuating means in which aA minimum of controls and piping are required to achieve the desired results.

These and other objects and advantages will become more apparent upon reference to the following description, taken in` connection with the accompanying drawings, in which:

Figure l is a perspective view of a typical blankholder press embodying an actuating means for the blankholder in accordance with the present invention;

Figure 2 is a sectional view indicated by line 2-2-2 on Figure l, showing the arrangement of the blankholder actuating means at one side of the press;

Figure 3 is a plan section indicated by line 3 3 on Figure 2 and showing the arrangement of one of the blankholder actuating means in the bed of the press;

Figure 4 is an enlarged view similar to Figure 2, but showing in greater detail one of the iluid operated blankholder actuating means at one corner of the press and the control system connected therewith; and

Figure 5 is a perspective View showing the construction of a movable valve member associated with the hydraulic circuit of one of the blankholder actuating means.

Referring to the drawings somewhat more in detail, the press illustrated in Figure l comprises a bed 10 and a head 12 with the head and bed preferably interconnected by some suitable strain rod means, not shown, and which may extend through the closed uprights 14 arranged on opposite sides of the press bed.

The press comprises a main pressing platen 16 connected with a ram that extends upwardly into the press cylinder in the press head. A reservoir 18 may be provided on top of the press head and there may also be arranged on the press head a pump connected with the y press cylinder, as by the conduit means 20.

Suspended below pressing platen 16 of the press is blankholder platen 22. Blankholder platen 22 may be dependent from platen 16 by rods 24, which are arranged in the usual manner to permit movement of the platens toward each other, but which will limit the amount which the platens can move away from each other.

By this means, when the main platen advances the blankholder platen also advances until it reaches its working position, and thereupon, the blankholder platen halts, and the main platen continues to advance to do its work. Thereafter, when the main platen is retracted, the blankholder' will remain in position until it is picked up by rods 24, and will thereafter retract in unison with the main platen.

Connected to each corner of the blankholder platen and extending downwardly therefrom into the press bedv is a pull-down rod 26.` These rods are for the purpose of supplying the proper blankholding force to each corner of the blankholder platen to cause the said blankholder platen to have the proper blankholding action on the workpiece being operated. This force will vary from a substantial thrust of the blankholder on the surface of the blank being worked, to a very light, and sometimes actually no pressure on the surface of the blank.

Referring now to Figure 2, it will be observed that each of the rods 26 is coupled, as by the coupling 2S, with a plunger 30 extending into a cylinder 32 and having connected therewith withinthe cylinder a piston 34'. Each piston. has connected' to its lower face, as by means of the flange 36, a tail rod 38 of the same diameter as plunger 30. These tail rods extend out through the lower ends of the cylinder and cause both faces of the pistons 34 to be of the same area, whereby the pistons can be reciprocated in the cylinders merely by exchanging fluid from one end to the other.

Referring now to Figure 4, the construction of one of' the iluid operated means for actuating the blankholders is illustrated more in detail. In Figure 4, it will be noted that the cylinder 32 illustrated therein comprises an axial passage 4t) extending along one side thereof that communicates by means of a port 42 with the upper end of the bore in the cylinder and also by means of a port 44 with a passage 46 formed in the head 48 that closes the lower end of the cylinder.

Passage 46 forms a chamber that is interrupted by a bore 50 opening into cavity 52 formed in head 48 and comprising a continuation of the bore in cylinder 32.

Passage 46 is also intersected by a somewhat enlarged threaded portion S4 in the periphery of head 48, and which is adapted for receiving the bored cap 56. Reciprocably mounted in the bore of cap 56 is a valve member 58 having its one end of a size that will closely lit in the bore in cap 56, and which is longitudinally grooved, as indicated at 60.

Longitudinal grooves 60 communicate with the annular groove 62 that is so positioned that when valve member 58 is in its Figure 4 position, passage 40 is communicated by means of grooves 62 and 60 with the right-hand end of the bore in cap 56.

The portion of valve member 58 toward the left end thereof is provided with a cylindrical projection 64 adapted for being closely received within bore 50, and immediately rightwardly of cylindrical portion 64 there is a tapered part 66 adapted for seating against a taperedvalve seat formed around the end of bore 50 where it communicates with passage 46. The length of cylindrical portion 64 is such that when valve member 58 is moved rightwardly from its Figure 4 position, the annular flange portion 68 of the valve member, which is located immediately leftwardly of groove 62, will enter and close the mouth of the bore in cap 56 at about the same time the said cylindrical part 64 opens the end of the bore 50, thereby to communicate the lower end of the bore and cylinder 32 with passage 40.

Figure 4 also illustrates the hydraulic circuit that supplies fluid to cylinder 32 and the control means associated therewith. The hydraulic circuit comprises a pump 70 connected by conduit 72 to draw fluid from a reservo-ir 74, which may be the same reservoir identified at 18 in Figure l, or which may be an independent reservoir. In either case, pump 70 and reservoir 74 are preferably mounted on the press head.

Pump 70 is arranged to discharge into an accumulator 76, and a relief valve 78 may by-pass the pump to relieve excessive pressure. Pump 70 may be of the constant delivery type, or may be variable delivery, with means being provided whereby the accumulator pressure regulates the stroke ofthe pump.

Conduit means leading from the discharge side of the pump to the accumulator also leads to the inlet port of a valve comprising valve body 82 and a valve member 84, reciprocably mounted therein. Also connected with valve body 82 is conduit 86 and a conduit 88 which latter leads through pressure regulating valve 90 to port 92 that opens into the bore in cap 56.

Valve member 84 is adapted for normally being positioned by a spring 94 in position to interconnect conduits 88 and 86 and is movable by energization of a solenoid 81 into position to communicate conduits 80 and 88.

The aforementioned reducing valve 90 is of substantially conventional type and will permit free iluid ow therethrough in either direction, until the pressure on the side toward the blankholder actuating means reaches a predetermined amount, and at which time this pressure 4 will be conducted by the pilot conduit 96 to the underneath side of piston 98, thereby causing the said piston to move upwardly against the thrust of spring 180, and thereby to throttle the fluid ow through the valve.

In this manner, a hydraulic pressure can be supplied to conduit 88 from conduit 80 and any predetermined pressure delivered through the reducing valve to the bore in cap 56.

lt will be understood that there is provided a separate one of the reducing valves for each of the several blankholder actuating means, and these may be supplied with uid from conduit 88, as by the branch conduits indicated at N2.

Each of the heads 48 attached to the lower ends of the cylinders 32 includes a small port 04 connected by the drain conduit l06 with the exhaust conduit 86. The purpose of ports 184 and drain conduits 106 is to relieve the cylinders 32 of excessive duid pressures at the time it is desired to retract the blank-holder and also serve to maintain the cylinders charged with iiuid at all times.

The charging of the cylinders comes about because the conduit 86 leads to a reservoir or tank positioned at a level substantially above that of cylinders 32, whereby continuous head is maintained on the iluid in the conduits 106, and thereby maintains a predetermined minimum pressure on the iluid in the several cylinders 32.

Solenoid S1 is connected between power lines L1 and L2 in series with a limit switch LS which is adapted for being actuated to its closed position by a cam 110 mounted on main platen 16. Cam 110 is so arranged that it engages and closes limit switch LS after the blankholder has come to rest on the blank and the main platen has made a predetermined further advancing movement. Cam 110 thus releases switch LS to its normally open position before the blankholder is picked up by the main platen during the retraction stroke of the press.

The operation of the blankholder actuating means ac cording to my invention is as follows:

When the main platen of the press is advanced, the initial movement of the blankholder platen is by gravity with the several blankholder pistons 34 moving downwardly in their respective cylinders 32 and displacing fluid from the bottoms of the said cylinders through bore 50, passages 40, and ports 42 into the upper ends of the cylinders.

When cam 110 engages and closes limit switch LS, solenoid S1 becomes energized and shifts valve member 84 to its Figure 4 position, thereby interconnecting pressure conduit and conduit 88 leading to the inlet of pressure reducing Valve 90.

The discharge from pressure reducing valve is delivered through port 92 into cap 56, and this moves valve member 58 leftwardly to its Figure 4 position. Pressure is then built up in passage 40 and the upper end of cylinder 32 according to the setting of pressure reducing valve 90, while the lower end of the cylinder remains at substantially exhaust pressure and sealed o from the high pressure iluid by the seating of valve member 48 in the end of bore 50.

Each of the several blankholder pistons could, of course, be subjected to a dilerent pressure in order to give the required blank-holding pressure at each portion of the blank being worked.

After the press platen has completed its work and commences to retract, it will tirst move cam to release limit switch LS and will thereafter pick up the blankholder platen. Releasing of limit switch LS will de-energize solenoid S1 and permit spring 94 to move valve member 98 leftwardly to connect conduit 88 with exhaust conduit 86. When the main platen then picks up the blankholder platen the fluid displaced from the upper ends of cylinders 32 will act on the several valve members 58 and move them rightwardly into the bored caps 56, thus once again opening the bores 50 so that further up- Ward movement of the pistons 34 in their cylinders 32 will grandes merely @Xchange m'd from'one end of the said cylinders to the other. V,

It will be appreciated that springs could be employed for biasing the valvemembers. 58 rightwardly, if so desited, but under all vnormal conditions of operation, the uid that is forced from passage 40 i'nto'the caps 56 will etfect this movement substantially instantaneously, whereby normally biasing springs of this nature are not required.

It will be understood that this invention is susceptible to modification in order to adapt it to dilferent usages and conditions, and, accordingly, it is desired to cornprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim: f Y

l. In a blankholder press having a bed and a blankholderplaten reciprocable relative to said bed, a plurality of cylinders mounted in spaced relation in said bed, a piston -in 'each said cylinder having its opposite faces equaland each piston being connected. with said blankholder platen, channel means in each said cylinder normally interconnecting the opposite ends thereof for the free exchange of luid between the said opposite ends, a valve means associated with each said channel means movable into position by iluid pressure to interrupt the said channel means, uid operable means for each valve means responsive to iluid pressure for moving the valve means into said position, a source of fluid pressure under pressure, means for conveying pressure from said source of pressure to the uid operable means of each of said valve means to move them into channel means interrupting position, each valve means including passage means for conveying the said fluid pressure to one end of the respective cylinder, and means comprising a reducing valve connected between said source of uid pressure and each of said cylinders, for exerting a selected predetermined pressure on each piston.

2. In a press; a bed, a main platen, a blankholder platen between said main platen and bed suspended from said main platen while being movable toward the said main platen, a cylinder in said bed, a piston in said cylinder having its opposite faces equal connected with said blankholder platen, a channel extending through said cylinder and normally hydraulically interconnecting the opposite ends thereof, a valve member movable into position for interrupting said channel, a uid operable area on said valve member responsive to uid pressure for moving the valve member into said position, a source of fluid pressure, valve means interconnecting said source of pressure with said uid operable area of said valve member for directing a supply of pressure to said area to move the said valve member into channel interrupting position, and passage means in said valve member responsive to movement of the valve member into said position for connecting said area to one end of said cylinder.

3. In a press having a bed and blankholder platen reciprocable relative thereto, a cylinder mounted in said bed, a piston in said cylinder having a tail rod extending out the lower end of said cylinder and having a plunger of the same area as said tail rod extending out of the top of said cylinder and connected with said blankholder platen, a channel extending along one side of said cylinder and ports at the opposite ends of said channel opening into the ends of said cylinder, a bore in alignment with one of said ports, said bore being closed at one end and opening into said channel at the other end, a valve member in said bore having one position where it engages and closes the said one port and having another position where it opens the said port for communicating said channel with the adjacent end of said cylinder, means for supplying fluid under pressure to the closed end of said bore for moving said valve member into its port closing position, and passage means associated with said valve member operable when said valve member is moved to its port closing position for interconnecting said channel with the closed end 0f said bore.

,4. In a piston and cylinder arrangement especially adapted for use as a blankholder platen actuating means, a cylinder, a piston in said cylinder having its opposite faces equal, channel means in said cylinder normally hydraulically Iinterconnecting the opposite ends thereof, avalve member having one position where said channel means is interrupted and another position where said channel means is established, means providing a bore \having one closed end in which said valve member is reciprocable, and means for supplying fluid under pressure to the closed end of said bore for moving said valve member into its channel means interrupting position, and restricted passage means associated with the valve member for connecting the closed end of said bore with the channel means on one side of said valve member when the valve member is in its channel means interrupting position. l

v 5. In a piston and cylinder arrangement of the nature described, a cylinder, a piston in said cylinder having its opposite faces equal, channel means in said cylinder normally hydraulically interconnecting the opposite ends thereof, a valve member having one position where said channel means is interrupted and a second position where said channel means is established, means associated with said cylinder providing a bore having one closed end in which said valve member is reciprocable, means for supplying uid under pressure to the closed end of said bore for actuating said valve member into its channel means interrupting position, and passage means associated with said valve member operable for interconnecting said channel means with the closed end of said bore when the said valve member is in its channel means interrupting position.

6. In a piston and cylinder arrangement of the nature described; a cylinder, a piston in said cylinder having its opposite faces equal, a channel extending along one side of said cylinder and a port at each end of said channel communicating the same with the adjacent end of said cylinder, means providing a valve bore having one closed end in axial alignment with one of said ports, a valve member reciprocably mounted in said bore and having its one end arranged to enter and close the said one port, means for supplying liuid under pressure to the closed end of said bore for moving said valve member into its port engaging position, and passage means associated with said valve member adapted for communicating the closed end of said bore with said channel means when the said valve member is in its port engaging position.

7. In combination; a cylinder, a piston having its opposite faces equal in said cylinder, a port opening into each end of said cylinder, a channel normally interconnecting said ports, means providing a valve bore in axial alignment with one of said ports, the end of said valve bore opposite the said one port being closed, a valve member reciprocable in said bore and having the end adjacent said one port reduced in diameter so as to enter said port, means for supplying iuid under pressure to the closed end of said bore, and passage means associated with said valve member for affecting restricted communication of the closed end of said bore with said channel when said valve member is in its port engaging position.

8. In combination; a cylinder, a port in each end of said cylinder and channel means interconnecting said ports, means providing a valve bore in axial alignment with one of said ports and one end of said valve bore being closed, a valve member reciprocably mounted in said bore and having its end adjacent said one port of reduced diameter, a conical portion on said valve member immediately behind said reduced diameter portion, a larger diameter portion immediately behind said conical portion, and a still larger diameter portionv closely iitting in said bore, an annular groove in said valve member in the largest diameter portion thereof so positioned that it opens into said channel means when said valve member is in its port engaging position and is within said bore when the valve member is away from its port engaging position, and other passage means in said valve member communieating the closed end of said bore with said annular groove.

9, In a press having a bed and a blankholder platen reciprocable relative thereto, a plurality of cylinders mounted in spaced relation in said bed, a piston in each said cylinder having its opposite faces equal and said pistons being connected with spaced points on said blankholder platen, channel means extending through each said cylinder serving normally to interconnect the opposite ends of said cylinders whereby said blankholder platen can be reciprocated freely relative to said bed, valve means carried by said cylinders for interrupting said channel means, fluid operable means associated with each said valve means responsive to fluid pressure for moving said valve means into position to interrupt the said channel means to which it pertains, passage means in each valve means operable upon actuation of the valve means by said uid operable means to connect each said fluid operable means with one end of the pertaining cylinders, and conduit means continuously exhausting the other end of each said cylinder.

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